Mayor Bloomberg called out powerful Assembly Speaker Sheldon Silver in the battle to reform bloated public-worker pensions, saying it’s state lawmakers who need to take on the unions — not City Hall.

“The unions were given pension benefits by the state Legislature, almost all, without the city’s involvement, and now Shelly says if you take them away the city’s got to be involved,” Bloomberg said on his weekly radio show yesterday.

“Why would a union leader ever negotiate with the city when they know that the state Legislature is going to give it to them or protect them anyways,” Bloomberg fumed.

The mayor’s saber-rattling appears to be having some effect.

Yesterday, the 2.5-million-member AFL-CIO postponed a planned TV ad blitz against Gov. Cuomo’s proposed pension reform after Silver (D-Manhattan) asked the labor group’s president, Mario Cilento, to hold off until the speaker had a chance to meet with the governor this weekend, sources said.

“If there’s an opportunity to do something peacefully, you take the opportunity,” one union leader familiar with the issue told The Post.

Capitol observers saw the development — days after Silver told Cuomo to “work out” a pension agreement with the unions — as a sign of progress toward a potential deal.

Cuomo is seeking to maximize his leverage by including his plan in the state budget due April 1.

He says state and local government would save $113 billion over 30 years through his plan, which requires future public employees to contribute more to their pensions and work longer before they can retire and before vesting sets in, prohibits the use of overtime to pad retirement payments and offers a 401(k)-style plan as an alternative to a traditional pension.

Even most union households support the plan, independent polls have shown.

Bloomberg also took to the state capital airwaves with Albany Mayor Jerry Jennings to make the case for Cuomo’s so-called pension Tier VI plan and said the fiscal future of the city and other localities is squarely in state lawmakers’ hands.

“Pension costs that were voted by the Legislature are just destroying the budgets from one end of New York state to the other, from small towns to the biggest cities, and we have to find a way out of this conundrum,” Bloomberg said on Albany’s Talk 1300 AM radio.

“Towns and counties across the state are starting to have to make the real choices: fewer cops, fewer firefighters, slower ambulance response, less teachers in front of the classrooms.”

Bloomberg said lawmakers are beholden to unions, which “raise money, they work at the polls, they write opinion pieces, they make phone calls, they go on social media and overload people with messages.”